1. Field of the Invention
The present invention relates to a hardness tester.
2. Description of the Related Art
In a typical hardness tester, an indenter is urged to a surface of a sample to form an indent, and hardness of the sample is determined on the basis of the size of the indent.
For example, to determine hardness of a sample with a Vickers hardness tester, the sample is positioned in the horizontal direction such that a point to be indented on a surface of the sample lies directly below an indenter, while is positioned in the vertical direction (focusing) at the point. A turret is then rotated to allow the indenter to face the sample, and a predetermined testing force is applied to the sample surface through the indenter to form an indent. The diagonal length of the indent is then measured, and the hardness of the sample is calculated on the basis of the measured length of the diagonal of the indent.
For such positioning using the hardness tester, a monitor displays a surface image of a sample captured by a camera and appearing on a main screen and operational bars for adjusting horizontal and vertical positions of the surface image appearing on the main screen. A user adjusts the position of the sample through the operation of the operational bars with a keyboard or a mouse while viewing the surface image on the main screen.
Unfortunately, such a tester involves the operation of the operational bars provided separately from the main screen; hence, the user must turn its eyes from the main screen to the operational bars for every operation of the operational bars. This precludes operability of the tester.
To solve such a problem, for example, a technique (see Japanese Unexamined Patent Application Publication No. H8-262327) has been proposed to be used for a stage of a microscope or a machining table of a machine tool, in which starting and stopping points are set on a screen through mouse operation, the respective X-Y coordinates of the starting and stopping points are detected, the moving distances in X and Y directions of the X-Y table are set on the basis of the coordinate values, and consequently the X-Y table can be automatically moved to a target position.
According to the technique, the X-Y table can be simply and accurately moved to an appropriate position in any direction merely through setting of the starting and stopping points.
Unfortunately, since the technique described in Japanese Unexamined Patent Application Publication No. H8-262327 simply relates to setting of the starting and stopping points on a screen through a mouse operation, an image cannot be continuously moved on the screen, leading to a difficulty in fine position adjustment. As a result, the technique cannot be applied to a hardness tester that requires fine position adjustment for accurate measurement, resulting in low operability of the tester.
In addition, Japanese Unexamined Patent Application Publication No. H8-262327 has no description on vertical position adjustment; hence, the technique cannot solve the low operability in the adjustment of a vertical position.